COL(C)                               UNIX System V



     Name
          col - filters reverse linefeeds


     Syntax
          col [ -bfxp ]


     Description
          col  prepares  output  from  processes,  such  as  the  text
          formatter  nroff(CT), for output on devices that limit or do
          not allow reverse or half-line motions.   col  is  typically
          used  to  process  nroff  output  text  that contains tables
          generated by the tbl program. A typical command  line  might
          be:

               tbl file | nroff | col | lpr

          col takes the following options:

          -b   Assumes the output device in  use  is  not  capable  of
               backspacing.   If  two or more characters appear in the
               same place, col outputs the last character read.

          -f   Allows forward  half  linefeeds.   If  not  given,  col
               accepts  half  line motions in its input, but text that
               would appear between lines is moved down  to  the  next
               full  line.  Reverse  full and half linefeeds are never
               allowed with this option.

          -x   Prevents conversion of whitespace to  tabs  on  output.
               col  normally  converts  whitespace  to  tabs  wherever
               possible to shorten printing time.

          -p   Causes col to ignore unknown escape sequences found  in
               its  input  and  pass  them  to  the  output as regular
               characters.  Because these characters  are  subject  to
               overprinting from reverse line motions, the use of this
               option is discouraged unless the user is fully aware of
               the position of the escape sequences.

          col assumes that the ASCII control characters SO (octal 016)
          and  SI  (octal  017)  start  and  end  text in an alternate
          character set.  If you have  a  reverse  linefeed  (ESC  7),
          reverse half linefeed (ESC 8), or forward half linefeed (ESC
          9), within an SI-SO sequence, the ESC 7, 8 and 9  are  still
          recognized as line motions.

          On input, the only control characters col accepts are space,
          backspace,  tab,  return, newline, reverse linefeed (ESC 7),
          reverse half linefeed (ESC 8), forward  half  linefeed  (ESC
          9),  alternate  character start(SI), alternate character end
          (SO), and vertical  tag  (VT).   (The  VT  character  is  an
          alternate  form  of  full  reverse  linefeed,  included  for
          compatibility with some earlier programs of this type.)  All
          other nonprinting characters are ignored.


     See Also
          nroff(CT), tbl(CT)


     Notes
          col cannot back up more than 128 lines.

          col allows at most 800 characters, including backspaces,  on
          a line.

          Vertical motions that would back up over the first  line  of
          the  document  are  ignored.  Therefore, the first line must
          not contain any superscripts.


     Standards Conformance
          col is conformant with:
          AT&T SVID Issue 2, Select Code 307-127;
          and The X/Open Portability Guide II of January 1987.


     (printed 2/15/90)                                     COL(C)